[explorer][s]: tweak colors on nodelink and move setting of colors to dedicated function for easier customization in future.
[explorer][s]: tweak colors on nodelink and move setting of colors to dedicated function for easier customization in future.

openspending/openspendingjs-old,openspending/openspendingjs-old,RCGTDev/openspendingjs,openspending/openspendingjs,openspending/openspendingjs-old,openspending/openspendingjs,openspending/openspendingjs-old,RCGTDev/openspendingjs,RCGTDev/openspendingjs,openspending/openspendingjs,RCGTDev/openspendingjs,openspending/openspendingjs